Protective means for buried metallic surfaces



g- 1932- s. u. MCGARY ETAL 3,871,125

PROTECTIVE MEANS FOR BURIED METALLIC SURFACES I Filed Oct. 11-. 1929 Patented Aug. 9, 1-932 UNITED STATES PATENT OFFICE STANTON U. MCGARY, WALTER F. ROGERS, AND STANLEY GILL, OF HOUSTON, ram,

ASSIGNORS 1'0 GULF PRODUCTION OF TEXAS COMPANY, OF HOUSTON, TEXAS, A CORPORATION rno'rncrrva means roa BURIED ME'rALnIc summons Application filed October 11, 1929'. Serial No. 399,079.

that'class of destructive agencies that arechemical in nature, and, secondly, those which are of a mechanical character. The destructive agencies ofthis latter class have been investi ated by the United States Bureau of Standards, and have been grouped by that Bureau into a general classification designated as soil stress effects. The primary object of the present invention is to provide means for combatting this soil stress efi'ect, and in carrying out this object, means are utilized that are capable of being applied to the metallic body, such as pipe, in the field by methods that are in use at the present time for the application of protective wrappings now being used in connection with pipe lines.

More specifically, the invention contemplates a protective means for pipe lines adapted to be buried in soil, such means consisting of a coating of non-corrodible material aplied directly to the surface of the body to e protected, this coating itself in turn being protected by a layer of metal sheathing of from .0005 inches to .010 inches in thickness.

In the accompanying drawing there is shown in Figure 1, partly in elevation and partly in section, a section of pipe covered with the protective means of the present in-' the surface of the bituminous or other coating which is to be protected against soil stress efi'ects. Also, materials in this range of thickness are so readily handled that they can be applied to pipe lines in the field, or at their point of use, by methods which are at present utilized in the application of cloth or like wrapping materials. with metal sheets of a thickness greater than the maximum above, mentioned, as thicker metal sheets must be applied by special methods, due to their rigidity. Further, thicker metal sheets will not stay closely and intimately in contact with the coating to be protected. As a consequence, the cost of thicker metal sheets is extremely high, due to the fact that they must be applied by special methods, and, due to the fact that they fail to make close contact with the material, their protective action is inferior to that of sheets of a thickness within the limits specified herein.

There is, of course, some advantage in using a metal sheathing highly resistant to the corrosive action of the soil, but this is by no means essential, as theprimary function of the sheathing is to overcome the destructive agencies in that class known as soil stress eifect. Similarly, it is not essential that this metallic sheathing adhere tightly to the protective coating, since its function is not to excludedestructive chemical materials, but to distribute and deflect those mechanical forces which tend to disrupt the protective coating material 11.

The metal sheathing 12 can be applied to the object to be protected in various ways, dependent somewhat upon the shape of the body. However, in the case of piping, the metal sheet is preferably applied in elongated strips wrapped helically around the .pipe, as is shown in that portion of the pipe This is not possible cal wrapping of metallic ribbon of foil thickness.

2. A soil stress and corrosion-resistant covering for buried metallic pipe comprising 7 5 a continuous corrosion-resistant coating covering the pipe surface, and an armor jacket for rotecting said coating from mechanical in ury by the soil comprisin a helical wrapping of single-ply metallic ri bon of 1 foil thickness.

3. A soil stress and corrosion-resistant covering for buried metallic pipe comprising a continuous corrosion-resistant coating covering the pipe surface, and an armor 15 jacket for protecting said coating from mechanical in ury by the soil comprlsing a helical wrapping of single-ply metallic ribbon of such flexibility as to be capable of manual application around the pipe and coating after 20 the pi e has been strung out, assembled, and coated? 4. A protective covering for metallic surfaces buried in soil of corrosive nature com prising a continuous corrosion-resistant coat- F5 ing covering the metallic surface and means for protecting said coating from mechanical injury due to soil stress phenomena comprising an armor jacket of flexible single-ply-corrosion-resistant metallic sheetin having a thickness of not less than .0005 0 an inch or more than .010 of an inch.

STANTON U. MOGARY. WALTER F. ROGERS. STANLEY GILL. 

